Fault Location In Distribution Feeders Containing Distributed Generation

1
Fault Location In Distribution Feeders Containing
Distributed Generation

• Darla King Adly A. Girgis
• IEEE Student Member IEEE Fellow

2
Outline

• Introduction of DG
• A Modified Fault Location Method?
• Overview of the Modified Zabc Method
• Analysis
• Future Research

3
Distributed Generation

• Fuel Cell
• Produces energy in the form of electricity and
  heat as long as fuel is supplied
• A fuel cell does not run down or require
  recharging
• Consists of two electrodes around an electrolyte
• Oxygen passes over one electrode and hydrogen
  over the other, generating electricity, water and
  heat

• Microturbine
• Small, high-speed generator power units
• Consists of a turbine, a compressor, and a
  two-pole permanent magnet generator
• Can produce from 25kW-100kW of power by
  conversion of fossil fuels.

4
Distributed Generation

• Wind Energy
• Wind generators produce power depending on wind
  speed.
• The wind is an indirect form of solar energy, and
  is therefore renewable
• Wind passing over the blades is converted into
  mechanical power, which is fed through a
  transmission to an electrical generator

• Solar Energy(Photovoltaic)
• Electricity can be produced from sunlight through
  a photovoltaics (PV) process
• solid-state electronic cell produces direct
  current electrical energy from the radiant energy
  of the sun.

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Why Is There The Need For A Modified Fault
Location Method?

• Introduction of Distributed Generation in
  Distribution Systems
• Unidirectional to Multi-directional power flow
• Need modified method to eliminate errors inherent
  with using older fault location techniques that
  do not account for distributed generation

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Zabc Method?

• What is Zabc Method?
• Uses Three-phase components
• Based on Steady-State Analysis During Fault
  Conditions

• Why Choose Zabc Method?
• Can be Applied to Balanced and Unbalanced Systems
  
• Does not assume ideally transposed lines
• Does not assume mutual coupling between phases
  are equal

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Modified Zabc Method
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Modified Zabc Method

• Solve for Initial Fault Distance Do
  (Without any contributions from the DGs)
• Example Single Line-To-Ground Fault

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Modified Zabc Method
Calculate Currents Fed From the DGs IDGj
Compare Dj and D(j1) D(j1) Dj lt 0.1
Distance to Fault D(j1)
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System
Is
Source
Idg1
Idg2
Idg3
DG3
DG2
DG1
L1
L2 L1
L3 L2
12.47KV System 100MVA Base L1 1.5 miles L2 L1
0.75 miles L3 L2 1.2 miles
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Data Preparation

• Pick a Particular Fault Location along the Line
• Fault Analysis
• Find Source Voltages
• Find Source Currents

12
Analysis

• Zabc Method
• Solve for Initial Distance to Fault
• Continue Iterative Process until Final Distance
  to Fault is Found
• Compare Distance Found to Actual Distance
• Determine Accuracy of Zabc Method

13
Analysis

• Single Line-To-Ground Fault
• Zabc Method
• Split System into 4 Sections
• Do lt L1
• L1 lt Do lt L2
• L2 lt Do lt L3
• Do gt L3
• Solve For VFabc
• Find All DG currents
• Find new fault current IF(j1)IFjIDGj
• Calculate new fault distanceD(j1)
• Repeat until D(j1) Dj lt 0.1

F
Is
IsIdg1
IsIdg1Idg2
Idg3
Source
Idg1
Idg2
Idg3
DG3
DG2
DG1
L1
L2 L1
L3 L2
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Results

• Iteration Process Yielded Dfinal3.0426 mi
• Compare Dfinal(3.0426 mi) to Dactual(3.05 mi)
• Error .243

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Results
Source DG1
DG1 DG2
DG2 DG3
Past DG3
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Future Research

• Reduce Errors in Fault Location Method Due to the
  Availability of Fault Data on Distribution Lines
• Method based on Voltage and Current Data at
  Beginning of Faulted Line Segment
• Consider Larger System and Account for Loads
• Test Zabc Method with new system

17
Future Research

• Construct Algorithm to convert the voltage and
  current waveforms into phasor quantities needed
  for fault location method
• Use an Electromagnetic Transients Program to
  simulate the voltage and current waveforms during
  fault conditions
• Obtain Actual Recorded Data from a Fault Recorder
• Test Zabc Method with Simulated Data and Actual
  Data

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Questions?